An Air France Airbus A330 jetliner flying from Rio de Janeiro to Paris with 228 people on board was missing over the Atlantic Monday after suffering an electrical short circuit when flying through strong storms, Air France Chief Executive Pierre-Henri Gourgeon said....

Mr. Gourgeon said the plane flew through an area of thunder and strong turbulence around 4:00 a.m. Paris time. At 4:14 a.m., Air France headquarters in Paris received automated maintenance messages signaling failure of several electrical components, he said.

What I am surprised about is that apparently the SAR authorities have little clue where to start looking. Does an Air France A330 have ADS? That should give at least an indication where it was when the failures occurred.

The news article makes it sound like the plane was struck by lightning or some other storm-related event happened.

I thought it was essentially impossible for lightning strikes to totally disable a modern airliner. My superficial impression is that planes are struck by lightning from time to time and that at worst some repairs may be needed. Extreme turbulence in the middle of thunderstorms is another story I guess. I am less sure of how bad the risk is at 30,000 feet or so, at cruise altitude. I believe that thunderstorms can rise up to 40,000 feet in some cases. I'm sure just from a comfort standpoint, an airliner would normally try to fly around or over thunderstorms when possible, but out over the Atlantic your airliner weather radar is probably not as powerful as one's ground-based, high-power Doppler radar sets.

I thought it was essentially impossible for lightning strikes to totally disable a modern airliner. My superficial impression is that planes are struck by lightning from time to time and that at worst some repairs may be needed.

A few of the planes at my company got hit. I pulled into the one stormy night, and the captain in the neighboring aircraft called me over to look. He had scorch marks on the nose of the plane, but no other visible damage up front. In the rear, the tail cone, complete with the lights and wiring, was missing. There were char marks around where the tail cone had been attached, and some dangling wires.

Everything else was perfectly fine. All the aircraft's electronics (radios, radar, computers, all of it) continued to operate normally. The crew did admit to being a bit startled when the blast hit them on the nose.

These "tweets" seem to provide a significant amount of detail that isn't so readily available elsewhere. Needless to say, I haven't searched the whole internet for such things but this web site seems to be reasonably useful, on balance.

Does anyone know of good web pages on the technical details of the Air France monitoring system that picked up the multiple electrical failures and sudden loss of cabin pressurization? Does this system transmit data to Air France at a reasonably high frequency? Does it have some ability to survive an in-progress disaster and keep transmitting information as the disaster unfolds or is it limited to transient, real-time data only as long as the avionics is in good condition?

I hope that the ocean is not too deep near the nominal crash site so that recovery of the airliner pieces is reasonably practical. I fear that they were well beyond the relatively shallow continental shelf and thus crashed into the deep ocean, making salvage much more difficult or perhaps impractical.

I did a small amount of searching about the nominal location of the crash, and some pages say it went down near the Google maps searchable "Fernando de Noronha" island. Based on quickly reviewing a few internet ocean depth maps, this part of the ocean is generally quite deep, although there are islands in the area.

Below is an excerpt from this article, re the nominal position:

"Last radio contact with the flight was at 01:33 UTC. The crew was in contact with the Atlantic Area Control Centre (CINDACTA III) when the flight reported over the INTOL waypoint, estimating TASIL at 02:20 UTC. INTOL is an RNAV waypoint located in the Atlantic Ocean, 565 km from Natal, Brazil. The TASIL waypoint is located 1228 kilometers from Natal. TASIL is at the border of the Recife FIR and Dakar Oceanic FIR. "

Modern jetliners aren't supposed to disappear from the sky without warning, as Air France Flight 447 from Rio de Janeiro to Paris did Monday.

The flight is presenting investigators with a major mystery: What spurred the plane's computerized brain to alert Air France's maintenance hub that the aircraft had significant electrical problems?

The automatic alert is puzzling for several reasons. For one, it suggests "that the plane didn't suffer a complete and sudden loss of electrical power," according to John Cox, a former U.S. airline pilot who now works as safety consultant. But barring an in-flight breakup, that would mean the crew should have been able to send out an emergency call. Air-traffic controllers never received one, though the Airbus A330 is designed with backup electrical capability to enable emergency transmissions.

Air-traffic controllers never received one, though the Airbus A330 is designed with backup electrical capability to enable emergency transmissions.

Slightly misleading, I would say. It depends on the type of electrical failures. If the 744 lost all its main busses, it only has the Left VHF as a comms backup ... not much use when you're in the middle of the ocean.

If turbulence caused structural damage (and, in turn, electrical wiring damage), then perhaps the crew were too busy trying to control the aircraft to send out a mayday. Perhaps the turbulence even injured the crew before they were able to tighten their seatbelts.

Too many variables as yet. The DFDR and CVR should provide an answer if the associated wiring wasn't damaged.

Airlines largely have their own equipment, both airborne and ground, to manage their technical operations. Although they probably buy the stuff from only a handful of vendors, there are significant differences between these backoffice systems not used for flying, but for operations management. It's part of their competitive edge.

As these boxes are usually bolt-on, they may (!! may) be relatively self-sufficient. I can imagine one of these boxes being designed to operate with planes nearly dead, i.e. on the ground during layover. If, and again this is speculation, IF Air France has such independent operations management boxes, it could be that it managed to get a final distress call out after everything else failed.

The DFDR and CVR should provide an answer if the associated wiring wasn't damaged.

Where are they?More than 24 hours after the aircraft disappeared, no one has any idea where it is.I start to think that if they don't find the crash site today, we will never know what exactly happened.

I have been following this story with interest and now the sad resignation that we must accept the worse case.

I do have some questions that have come up:-

In terms of the black box, what is the media inside that is used to record the data?Assuming that this aircraft was lost where the few parts have to date been found, what is the surviability of the black box? I mean we are in area where the sea is potentially 7000m deep from what I have read? So does the black box stay afloat? Does it have a transmitter that can assist in locating it? If so what is the range of the transmitter?

As well as sensors from the aircrafts systems, does the black box have sensors to give independant readings e.g., G forces, altitude etc.?

A further thought - Is this the farthest away from land that an aircraft has been lost?

I have been following this story with interest and now the sad resignation that we must accept the worse case.

I do have some questions that have come up:-

In terms of the black box, what is the media inside that is used to record the data?Assuming that this aircraft was lost where the few parts have to date been found, what is the surviability of the black box? I mean we are in area where the sea is potentially 7000m deep from what I have read? So does the black box stay afloat? Does it have a transmitter that can assist in locating it? If so what is the range of the transmitter?

As well as sensors from the aircrafts systems, does the black box have sensors to give independant readings e.g., G forces, altitude etc.?

A further thought - Is this the farthest away from land that an aircraft has been lost?

Regards

Carl

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Carl,

Below is an excerpt from a recent online news article, and it contains some information regarding the detection of the black box recording devices underwater, range of detection, etc.

By my own guesses and informal research, the depth of the ocean in the region of the debris field is so deep (over 10,000 feet) that recovery of the black box will be very hard. I am guessing that much will depend on how accessible the recording boxes are and how fragmented the aircraft's pieces are. Previous mid-air explosions over the ocean have yielded some fairly large segments with a huge number of small pieces.

The data and cockpit voice recorders could even be buried in a complex pile of tangled wreckage. Based on watching a few TV shows, undersea robots can do a limited amount of underwater salvage and recovery at these depths IF they can find the black boxes before their underwater beacons run out of batteries in about 30 days.

News article excerpt:---------

The fastest path may be focusing on the recorders' emergency signal, said Barry Cairns, a sales manager at Sonardyne International Ltd., a company outside London that specializes in undersea navigation and positioning, largely for the energy industry. Sonardyne in 2006 helped retrieve the black boxes from an Armenian Airbus jetliner that crashed in the Black Sea.

Typically, searchers drag a sensor from a ship that traces a grid on the surface. The smaller the search area, the faster the sound is likely to be detected. Once the signal is heard, computers can pinpoint its source quickly, Mr. Cairns said.

Undersea, the signal can carry for roughly 3,300 feet, so "it all depends on how deep the black boxes have gone," he said.

One factor that makes this accident so unusual is the remoteness of the apparent crash site and the depth of the water there, which could exceed 13,000 feet, roughly the depth of the Titanic.

I don't get why there is such a tendency to blame modern fly-by-wire/computerized airliners - the accident rate is at an incredibly low rate now due to the superiority of these software-based systems. While no such system will ever be perfect and nothing this complex can possibly be perfect under all circumstances, these are surely among the most reliable systems mankind has ever created. The accident and incident rate is so low it is statistically all but impossible to improve them, IMO. I don't know of any statistics supporting that Airbus is less reliable than other vendors, and the number of accidents is so low that any numerical differences in accident rates would probably be statistically insignificant. The number of events is just too low to use statistics, and without statistics it is very hard to say anything meaningful about such things.

Below are some excerpts from this article. It's apparent that the lawyers have as usual become involved, hoping to obtain their usual large sums of money from the airlines and the aircraft companies. I assume the suit will be files in the USA with our unfortunate history of huge jury awards for damages, etc. Unfortunately, in the USA truth is not too much of an issue - only the ability of the lawyers to convince a jury of mostly poorly educated ordinary citizens. Typically, the companies being sued just settle out of court to avoid the worst case scenarios of a jury trial.

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A law firm representing victims of a previous serious incident involving an Airbus A330 warned that the aircraft could be vulnerable to electrical interference.

London-based Stewarts Law is preparing to sue Airbus, the Australian airline Qantas and a computer manufacturer, on behalf of 30 people injured when an A330 suddenly plunged 650 feet in flight last October. Air accident investigators blamed the rapid descent at 37,000ft over Western Australia on a malfunctioning computer system. The A330 is a "fly-by-wire" aeroplane that uses an air data computer to guide the aircraft and, if necessary, amend pilot errors.

The A330 has flown 707 million passengers since its launch 15 years ago and this week's crash was its first fatal incident in active service. But in the Qantas case, the aircraft's main navigational tool, the air data inertial reference unit, started emitting "electronic spikes" and plunged the A330 into a dive after mistakenly calculating that the aircraft was pitching its nose into the air. In fact, the aircraft was flying level.

According to one theory being examined by lawyers, the Airbus computer systems could have been affected by inadvertent interference from a nearby naval communications station. Jim Morris, a senior associate at Stewarts Law, said the Air France crash had again raised fears about the aircraft's susceptibility to electromagnetic interference. "It could be that if the A330 is more vulnerable to electromagnetic interference, it could have caused the pilots to lose control of the aircraft during severe turbulence," he said. He added: "The indications from the aircraft's datalink system are that there was a loss of electrical systems in a very short space of time, which indicates that there was a catastrophic failure."

A very good mate of mine is F/O on the A330 here in Australia. With respect to the ongoing problems with AIRDU units installed on the A330, apparenlty the Airbus guys are completely unsure as to what is causing the problems with uncommanded auotpilot inputs. They know what is happening, just can't pin down a specific cause. Airbus technicians at a recent briefing essentially blamed H******ll as the unit is supplied by them.

My mate's simplistic explanation of the new unofficial procedure when the A330 suffers an "upset" is to switch OFF the "flight computers" and very briefly revert to the redundancy system. Then after a short time, re-start the computers. BUT, don't quote me on that procedure, as there was a large quantity of amber fluid consumed prior to and during that conversation.

Seems to me that the B744 systems offer an older but far more stable and confident option.

I read an airline magazine real life story about a US Air pilot whose trans-Atlantic airliner's navigation computers lost their way for no apparent reason during flight, part-way across the pond. His First Officer had to manually track their position every 5 minutes all the way to Heathrow - they were advised by maintenance not to reboot the computers since it might make things worse. After the plane landed, the maintenance staff saw that the system was not working properly but after it was rebooted they could not reproduce the error condition. I'm not sure I would have wanted to be the next crew heading back across the Atlantic with that plane!

Intermittent errors and problems with any system can be terribly hard to diagnose and repair. We've all had that experience with automobiles, even back in the day when they were mechanical and not rolling computer networks. I'm not sure ANYTHING other than the steering and parts of the braking system and the wheel bearings and tires on my Volvo AWD S60 is directly mechanical. Even the door locks are merely signals sent to a networked computer which then controls a solenoid.

As the old IBM mainframes used to say about almost every error condition: "IHC 240I - Probable user error." I came to really hate that message.

In terms of the black box, what is the media inside that is used to record the data?

Well, an aircraft of this generation should have a Cockpit Voice Recorder(CVR) and a Dignital Flight Data Recorder(DFDR) with a solid state memory (i.e. completely shockproof). There will still be aircraft around, however, with magnetic tape recorders, but these are designed to operate under high g forces and will survive catastrophic g forces. These two types are generally interchangeable, however, so I couldn't be sure what type was fitted.

A typical black box memory will be encased in several layers of fairly thick metal (these boxes are quite heavy and definitely do not float) and may have a water jacket around one layer. In intense heat, the water turns to steam, and steam generally is limited to a specific temperature range well below the intense heat of an aircraft fire.

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Assuming that this aircraft was lost where the few parts have to date been found, what is the survivability of the black box?

The two black boxes generally survive most accidents. This is partly because they are located in the tail area, which seems to remain fairly intact even in bad accidents. The boxes can be found on electronic racks with, I recall, spring and rubber, shockmounts.

There is an ultrasonic beacon/transmitter mounted on the front of most black boxes which activates on contact with water (the water provides a conductive medium for the circuits to start working) By the way, most of these boxes are painted in a fluouro orange colour with reflective stripes stuck on the side, so this does help searchers, in many cases, to visually locate and identify the boxes. Ultrasonic transmitters are required as radio waves don't go very far underwater. The figures given for transmitter battery life are probably worst case scenario. The batteries have a "shelf life" of many years and are renewed periodically. The battery could be new.

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As well as sensors from the aircrafts systems, does the black box have sensors to give independant readings e.g., G forces, altitude etc.?

Not sure about the A330, but the 747-400 has a dedicated accelerometer mounted in one of the main gear wheel wells. Considering the wreckage was reportedly spread over a very wide area in this particular incident, I'm guessing the aircraft was breaking up before it hit the water, so there is no guarantee that the accelerometer would still be working (or, indeed, the black boxes themselves).

Many aircraft also have another emergency transmitter mounted on top of the fuselage, near the tail which automatically transmits UHF and VHF signals when high g forces are experienced. However, if this particular part of the fuselage is underwater, then it will be basically useless.